Anterior Fontanelle Closure and Size in Full-Term Children Based on Head Computed Tomography

Abstract

INTRODUCTION: This study investigates radiographically acquired normative ranges of anterior fontanelle closure (AFC) and surface area (SA) in healthy full-term infants. METHODS: High-resolution head computed tomography (CT) scans were retrospectively reviewed for AFC and AF dimensions to allow approximation of AF SA. RESULTS: Between 15 and 23 head CT scans per monthly age-group (0-24 months) were reviewed, totaling 464 scans. AFC frequency increased steadily from age 10 (16%) to 20 months (88%), reaching higher than 50% at age 16 months (53%). The AF was closed in 3% to 5% of infants at 5 to 6 months. AF median SA increased from 769.3 mm(2) (age 0 months) to 1022.2 mm(2) (2 months), then declined steadily. CONCLUSIONS: This study provides reference charts detailing AFC frequency and AF SA as a function of age. Wide variability of AFC timing and AF size among healthy infants suggest that early or delayed AFC may represent normal variants.